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Deputy judiciary chief Gholamhossein Mohseni-Ejeie said the sentencing decision was taken by an Iranian court

A US national has been sentenced in Iran to 10 years in prison on spying charges, Iranian officials have said.

The man was identified by judicial sources as Chinese-American Xiyue Wang, a 37-year-old researcher from Princeton University.

Wang was arrested last August as he tried to leave the country, according to the judiciary's news agency.

The US State Department called on Iran to release all those held on "fabricated" charges.

The sentence was announced on state TV by deputy judiciary chief Gholamhossein Mohseni-Ejeie.

Mizanonline, the Iranian judiciary's official news agency, said Wang was part of "an infiltration project" that sought to gather "highly confidential articles" for US and British institutions including the US State Department, Princeton University, Harvard Kennedy School and the British Institute of Persian Studies.

"Before his arrest he was able to digitally archive 4,500 pages of the country's documents while under covert surveillance," the agency said.

Sentence 'can be appealed'

Earlier this year, the authorities in Tehran said as many as 70 people they described as spies were serving sentences in the capital's jails.

The identities of only a handful have been made public.

"This person, who was gathering information and was directly guided by America, was sentenced to 10 years in prison, but the sentence can be appealed," Mr Ejeie said on Sunday.

He said the decision was taken by an Iranian court, without giving any further details.

In a statement, the US Department of State did not refer to any specific person but called on Iranian authorities to release all foreign citizens it is holding "unjustly... so they can return to their families".

"The Iranian regime continues to detain US citizens and other foreigners on fabricated national security-related charges," an official said.